**T1 Example checker (NEW).**
- Repo and paths: omnibase_core `src/omnibase_core/validation/checker_example.py`
- Configuration: every pattern and threshold is a `parameters` entry of the contract
- Bindings: the report writer and the bus bind from the overlay
- Declared: the handler is resolved from the container with get_service
- Two overlays: the runtime runs on the in-memory default and on the broker overlay with no code change
- Zero literal: hardcoded_topic, url_authority and contract_config_compliance report zero on the changed source
- Replay: disabling a rule row fails its fixture
